Post "Revisiting my email server in 2022"

1 files changed, 4 insertions, 2 deletions

diff --git a/content/know/concept/calculus-of-variations/index.pdc b/content/know/concept/calculus-of-variations/index.pdc
index a8861cb..26c5753 100644
--- a/content/know/concept/calculus-of-variations/index.pdc
+++ b/content/know/concept/calculus-of-variations/index.pdc
@@ -14,7 +14,7 @@ markup: pandoc
 # Calculus of variations
 
 The **calculus of variations** lays the mathematical groundwork
-for Lagrangian mechanics.
+for [Lagrangian mechanics](/know/concept/lagrangian-mechanics/).
 
 Consider a **functional** $J$, mapping a function $f(x)$ to a scalar value
 by integrating over the so-called **Lagrangian** $L$,
@@ -28,6 +28,8 @@ If $J$ in some way measures the physical "cost" (e.g. energy) of
 the path $f(x)$ taken by a physical system,
 the **principle of least action** states that $f$ will be a minimum of $J[f]$,
 so for example the expended energy will be minimized.
+In practice, various cost metrics may be used,
+so maxima of $J[f]$ are also interesting to us.
 
 If $f(x, \varepsilon\!=\!0)$ is the optimal route, then a slightly
 different (and therefore worse) path between the same two points can be expressed
@@ -238,7 +240,7 @@ $$\begin{aligned}
 
 ## Constraints
 
-So far, for multiple functions $f_1, ... f_N$,
+So far, for multiple functions $f_1, ..., f_N$,
 we have been assuming that all $f_n$ are independent, and by extension all $\eta_n$.
 Suppose that we now have $M < N$ constraints $\phi_m$
 that all $f_n$ need to obey, introducing implicit dependencies between them.